A pion beam line option for LBNF - nuPIL Outline Introduction - - PowerPoint PPT Presentation

A pion beam line option for LBNF - nuPIL

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Outline

• Introduction
• Updated design overview
• Neutrino flux comparison
• Physics comparison
• Details of design
• Engineering considerations
• Conclusions and moving forward

July 21, 2016 2

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Credits

Jean-Baptiste Lagrange Jaroslaw Pasternak Imperial College London AB Pilar Coloma Ao Liu David Neuffer Milorad Popovic (working on independent concept) Fermilab Terry Hart University of Mississippi Elizabeth Worcester BNL

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Total effort is only ~ 1.5 FTE

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Introduction

• The basic concept is to design a sign-selected,

large acceptance (transverse and in momentum) pion beam line.

– neutrinos from a pion beam line: nuPIL

• Send only pions in desired momentum range

towards DUNE detector (40kT LAr assumed in what follows.

– Of course, protons/kaons/muons in the same momentum band will follow along

• Ideal configuration: have a 5.8o bend matched

into a straight transport beam line (~200m)

• Basic design evolved from the pion injection

beam line for nuSTORM.

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

nuPIL advantages I

Beam systematics

• Beam systematics concerns for conventional horn-focused ν beam

line:

– Secondary particle production

• Particle types, flux and energy distribution

– Proton beam targeting stability – Target degradation/change – Horn stability – Target/Horn module mass uncertainty

• Water, supports, etc.
• Since the pion flux is measured in situ by the beam line

instrumentation (flux, momentum distribution, emittance), the above are largely factored out.

– Some R&D on instrumentation is needed, but work began and vendor contacts have been initiated. – Can also include commissioning/calibration runs that utilize destructive (for the beam) instrumentation

• In addition the ν background in the anti-ν beam (& vice versa) is

significantly reduced

– Some issues with new bend lattice

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Beam systematics II Diagnostics

Quantity Detector(s) Comments

Beam Intensity Beam current transformers <1% resolution obtainable Beam Position BPMs 1 cm resolution Beam profile Scintillating screens, etc Destructive Energy Polarimeter <1% resolution Energy spread Profile measurement in bend Beam loss Conventional Timing Conventional Pion/proton separation

• Beam can be fully characterized, including

destructive methods during a commissioning phase

• Magnet currents can be monitored and

controlled with precision

• all magnets are DC

Instrumentation for the beam line (straight)

Parameter Uncertainty Intensity 0.3% Divergence 0.6% Energy spread 0.1% Total ≤ 1%

nuSTORM study

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Update since May CM

• New bend with wider momentum acceptance
• Horn optimization for this bend

– 4 λ long C target

• Match into straight beam line
• Transport (~200 m) in beam line

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

nuPIL ν flux comparison May CM & now

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This represents a 42% increase in flux

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

nuPIL Lattice13-Hybrid vs. LBNF/DUNE 3-Horn Opt

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

CP violation sensitivity from Elizabeth W.

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π /

CP

δ

• 1 -0.8 -0.6 -0.4 -0.2

0.2 0.4 0.6 0.8 1

2

χ ∆ = σ 1 2 3 4 5 6 7 8

CP Violation Sensitivity

π /

CP

δ

• 1 -0.8 -0.6 -0.4 -0.2

0.2 0.4 0.6 0.8 1

2

χ ∆ = σ 1 2 3 4 5 6 7 8

DUNE Sensitivity Normal Hierarchy years ν + ν 3.5+3.5 = 0.085

13

θ 2

2

sin = 0.45

23

θ

2

sin

σ 3

σ 5

CDR Optimized Design 3-horn Optimized Design nuPIL Design

CP Violation Sensitivity

• Sensitivity calculations

produced by Elizabeth Worcester

• Flux for LBNF beams

produced by Laura Fields

• Flux for nuPIL beam provided

by Ao Liu

• Unless otherwise noted, all

configurations (GLoBES code,

• scillation parameters,

systematic selection efficiencies, etc) are identical to those used in the CDR

• LBNF optimized: identical to

“optimized design” in CDR, but with 204 m DP

• LBNF 3-horn optimized:

updated LBNF optimized design with improvements including, but not limited to moving to 3-horn design.

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Hierarchy

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π /

CP

δ

• 1 -0.8 -0.6 -0.4 -0.2

0.2 0.4 0.6 0.8 1

2

χ ∆ 5 10 15 20 25

Mass Hierarchy Sensitivity

π /

CP

δ

• 1 -0.8 -0.6 -0.4 -0.2

0.2 0.4 0.6 0.8 1

2

χ ∆ 5 10 15 20 25

CDR Optimized Design 3-horn Optimized Design nuPIL Design

DUNE Sensitivity Normal Hierarchy years ν + ν 3.5+3.5 = 0.085

13

θ 2

2

sin = 0.45

23

θ

2

sin Mass Hierarchy Sensitivity

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

3σ coverage over 75%

• f δ range (Pilar Coloma)

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NuPIL - Latt.13 DUNE CDR

0.0 0.2 0.4 0.6 0.8 1.0 1 2 3 4 5 6

δ

σ

3.5 + 3.5 years

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Normalization uncertainties

• I also asked Elizabeth to plot a case with the

current estimates for the normalization uncertainties for LBNF/DUNE and nuPIL/ DUNE

– LBNF/DUNE: Taken from the case made in the CDR = 5⊕2 – nuPIL: With beam line instrumentation and from studies done for nuSTORM: 4.5⊕1.5

• This was done for a large exposure

– 10.4 + 10.4 years

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

CP Violation sensitivity

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π /

CP

δ

• 1 -0.8 -0.6 -0.4 -0.2

0.2 0.4 0.6 0.8 1

2

χ ∆ = σ 2 4 6 8 10 12

CP Violation Sensitivity

π /

CP

δ

• 1 -0.8 -0.6 -0.4 -0.2

0.2 0.4 0.6 0.8 1

2

χ ∆ = σ 2 4 6 8 10 12

DUNE Sensitivity Normal Hierarchy years ν + ν 10.4+10.4 = 0.085

13

θ 2

2

sin = 0.45

23

θ

2

sin

σ 3 σ 5

CDR Optimized Design 3-horn Optimized Design nuPIL Design CDR norm. unc.

• Est. nuPIL norm. unc.

CP Violation Sensitivity

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

EW’s plot shown at CM

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• The take away from this

plot is that if, for some reason, your normalization uncertainties are larger than anticipated, the precision of this measurement will degrade quickly

• Starting off with

anticipated smaller normalization errors leaves more room.

• A well controlled

measured beam line as in nuPIL has the potential to be a great advantage

Configuration Details

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Schematic

Section view

• Target Hall complex at MI depth (could raise to surface level)
• “Conventional” target+horn(single) + 5.8° bend + production straight

(204m)

• Bend: sign and momentum selection

– With 2.4MW on target there is now ~ 145 kW in the beam

• Production straight: transport of beam to end of decay straight.
• ~110 kW pions + ~30 kW protons at beginning
• ~35 kW + ~17 kW = ~42 kW at end & into absorber (+ ~25 kW in muon)

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

“Waste power” mitigation

• “Waste power” is kept at MI depth.

– Less problematic than dealing with underground (cheaper)

• Since no line-of-sight from target to production straight,

unwanted charged particles and neutrons can be absorbed at/near surface level in the target hall complex.

– Will show preliminary MARS results. – Power going underground limited to ~ 145 kW (2.4MW on target)

67 kW 145 kW 2.4 MW

Primary absorber

Plan (TOP) view schematic One concept for Absorber hall

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

nuPIL

Current status

• FFAG 5.8o bend

– Double achromat Bend: 4 FDF triplets (12 magnets)

• 3 Quad match into beam line straight
• Quad triplet (FDF) straight beam line
• This is a hybrid system: FFAG - Quad

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Note: Aperture stops for wrong-sign π only introduced after magnets 11 & 12 at present

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Beam propagation through the bend

π+ decay off

After horn After dispersion creator After bend cell 1 After bend cell 2 (end) At end of decay pipe

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

ν production straight

• The π decay beam line channel (production

straight, formally known as a Decay Pipe) is a 200 meters long straight beam line consisting

• f a total of 27 quadrupole magnets. The first

three quads match the optics after the FFAG steering bend to the periodic cell optics, which is defined by a triplet cell (FDF).

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G4Beamline visualization: Red vertical bands are quads

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Tunability

• General nuPIL tuning:

– Horn current can be adjusted (within certain margins) for input matching – Ratio of B field in the F and D (focusing/de-focusing) magnets allows for the adjustment of non-bending plane optics – Bending plane tuning of magnets will allow one to adjust bending plane trajectory – Non-bending plane correctors (one per cell) should be enough for non-bending trajectory adjustment

• Example (LowE tune for Lattice 13):

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Trajectories for 0.85 GeV/c, 1.75 GeV/c and 3.6 GeV/c pions in “tuned” Lattice 13. High_E (tau) work in progress.

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Lattice 13 Beam Power Loss

• Yes, this is a problem

– ~40 kW of useful pions + ~12 kW protons

• Note: 35 kW of pion power produces the Lattice 13 ν flux
• Approach:

– Optimize match and Quad lattice, run GA, repeat – What can’t be made “useful” (transported to end) – absorb (apertures) in bend (TS)

July 21, 2016 23

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Engineering considerations

• The nuPIL configuration does add active

components in the target station.

• Can they survive?
• A MARS simulation of a “parameterized” TS

has been performed.

• Magnets simulated with cylindrical symmetry

with 80 cm bore and 1m Fe annulus outside bore as return yoke.

• Uniform (dipole) magnetic filed in bore

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

MARS model

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White: Vacuum Red: Iron Grey: Concrete Purple: Poly

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

MARS – 5 GeV/c pions

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C target set to vacuum

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

MARS: 80 GeV protons on C

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

MARS: Energy deposition

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• Largest dose is in magnet 1

bore (coils)

– Note: Magnet 3 is acting as primary proton beam stop in this model. (Not good engineering practice)

• This dose ~2 X 10-6 GeV/g-
• POT. The technology we

envision using here are MgO insulated magnets as developed in Japan and used at J-PARC. Lifetime of 1011 Gy

– Hirose et al., IEEE

TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 22,

• NO. 3, JUNE 2012
• This would correspond to 20

years of running at 2.4 MW.

• Also, very little radiation

dribbling out of back of TS

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Target station design

• The baseline design for LBNF follows the

design for NuMI

– To a large extend, it is the NuMI TS at surface

• This configuration does not accommodate the

nuPIL components very easily

• TS design the NF Study 1

– ORNL/TM-2001/124 “Support Facility for a Mercury-Jet Target Neutrino Factory”, September, 2001.

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

NF TS Design

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

NF TS Design II

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

NF TS Design III

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

NF TS Design IV

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Conclusion

• Using a pion beam line after a high-power target/

horn module presents an exciting possibility for producing a νµ beam for long-baseline ν oscillation experiments

– Comparable physics performance. – Much higher beam quality w/r to beam purity

• Lattice 13 “wrong-sign” bkg reduction - work in progress

– Beam systematics uncertainties reduced

• Neutrino beam flux determined directly from parent

particles, not induced from other experiments or MC.

• Uncertainties reduced by possibly a large factor due to the

beam line instrumentation

– Underground radiological issues essentially removed

• At this stage of the analysis, the nuPIL concept is

cost neutral

July 21, 2016 34

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Moving forward

• Continued work

– We are still on a sharp rising curve w/r to further

• ptimization.
• Improved flux by ~40% since CM
• Expect further significant improvement.

– Things to study:

• Look at 60 GeV protons
• Target/Horn design

– Our horn efficiency is only ~40% compared to 70% (NuMI)

• Match & Beam line lattice optimization

– May include iteration on the bend too

• Apertures in bend

– Losses in production straight

• Address Eν tuning to both lower and higher Eν

– Which is more important first?

July 21, 2016 35

Backup

Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

Pion Instrumented Line (nuPIL)

X X X

Eliminate µ storage capability

X

1300 km Residual high energy protons bend down 2.9° bend down 2.9° π d e c a y i n t h e s t r a i g h t

Target Station

nuSTORM

π + → µ+ +νµ µ+ → e+ +νe +ν µ David Neuffer, Ao Liu 2 km Ao Liu, JB Lagrange Kill the STORM part

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

FFAG “C” magnet (bend)

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Alan Bross | DUNE Accelerator and Beam Interface Group Meeting

nuPIL Horn sketch

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500 1000 1500 2000 2500 3000 3500 4000

Z (mm)

50 100 150 200 250 300 350 400

Y (mm) Optimized horn for lattice 11/13, with 160 cm Carbon target

195397.38